Core-shell structured quaternary energetic material and its preparation method and application

Abstract

The application provides a kind of core-shell structure quaternary energetic material and its preparation method and application, wherein the preparation method comprises the following specific steps: S1: nano magnesium powder and potassium nitrate powder are dissolved in organic solvent in turn, and Mg / KNO3 energetic slurry is obtained by heating and stirring;S2: nano aluminum powder and PTFE powder are treated by ultrasonic to obtain metastable mixed powder, then the metastable mixed powder is added to the prepared polymer binder, and Al / PTFE metastable composite slurry is obtained by heating, stirring and evaporation treatment;S3: the Mg / KNO3 energetic slurry obtained in S1 and the Al / PTFE metastable composite slurry obtained in S2 are added to two different barrels of 3D printer respectively, the equipment parameters of 3D printer are adjusted, and the Al / PTFE / Mg / KNO3 quaternary energetic material with core-shell structure is processed.The quaternary energetic material of the application can reduce the ignition temperature of the existing composite system material, further reduce the carbon residue formed after combustion, and the processing technology is simple, which can meet the personalized forming demand.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of energetic materials, and relates to a core-shell structure Al / PTFE / Mg / KNO3 quaternary energetic material based on an additive manufacturing technology and a preparation method and application thereof. BACKGROUND

[0002] Al / PTFE (aluminum / polytetrafluoroethylene) metastable composite material as a special energetic material has been widely concerned due to its high reaction energy release, relative stability and safety. However, among the existing problems of the Al / PTFE system, one is that a large amount of residues is left after reaction, and there is a lack of oxygen-containing substances to be converted into gas to improve the gas production of the system; the other is that the initial reaction temperature of the system reaches 400 DEG C, and the main reaction is at nearly 500 DEG C, so high reaction threshold value leads to that the system is not outstanding in actual application, so that the system is less used in the production and manufacturing of actual products. In addition, in the field of energetic materials such as explosives, there is still a problem of difficult forming and processing of energetic materials, and based on different bearing equipment and space, there is a demand for more refined and personalized customization of the sizing process. SUMMARY

[0003] In view of this, the application embodiment provides a core-shell structure Al / PTFE / Mg / KNO3 quaternary energetic material based on an additive manufacturing technology and a preparation method and application thereof. On the basis of the traditional Al / PTFE system, the Mg / KNO3 (magnesium / potassium nitrate) system is introduced to reduce the reaction temperature of the whole energetic material and reduce the combustion residue. At the same time, the additive manufacturing technology (also known as 3D printing technology) is used to cooperate with a special processing and forming process to generate a core-shell structure quaternary energetic material to ensure the further optimization and personalized customization demand of the combustion performance of the energetic material.

[0004] To achieve the above effect, the first aspect of the application provides a preparation method of a core-shell structure quaternary energetic material, characterized in that the method comprises the following specific steps: S1: nano-magnesium powder and potassium nitrate powder are dissolved in an organic solvent in sequence, and Mg / KNO3 energetic slurry is obtained by heating and stirring; S2: nano-aluminum powder and PTFE powder are treated by ultrasonic treatment to obtain metastable mixed powder, and then the metastable mixed powder is added to a prepared high molecular binder, and Al / PTFE metastable composite slurry is obtained by heating, stirring and evaporation treatment; S3: the Mg / KNO3 energetic slurry obtained in S1 and the Al / PTFE metastable composite slurry obtained in S2 are respectively added to two different barrels of a 3D printer, the equipment parameters of the 3D printer are adjusted, and the two are respectively collected in a nozzle with a double-channel blocking effect, and then extrusion forming is performed to obtain a core-shell structure Al / PTFE / Mg / KNO3 quaternary energetic material.

[0005] Optionally, S1 specifically comprises: S11: dissolving nano-magnesium powder in sufficient glycerol, heating and stirring until fully dissolved, and then cooling to room temperature to obtain a concentrated magnesium metal solution; S12: dissolving potassium nitrate powder in sufficient glycerol, and fully stirring to obtain a nitro solution; S13: adding the concentrated magnesium metal solution prepared in S11 into the nitro solution prepared in S12 in batches, and gradually evaporating the glycerol solvent by heating and stirring to control the overall viscosity of the mixed solution, to obtain a Mg / KNO3 energetic slurry.

[0006] Optionally, in S11, the particle size of the nano-magnesium powder is 100 nm, the heating temperature is 40-50℃, and the stirring rate is 30-45 r / min; in S13, the heating is to raise the temperature from room temperature to 40℃ at a speed of 1.6℃ / min, and the stirring rate is 40 r / min.

[0007] Optionally, S2 specifically comprises: S21: fully dissolving fluororubber in ethyl acetate to obtain a high molecular adhesive; S22: blending nano-aluminum powder with PTFE powder, and obtaining a metastable mixed powder after ultrasonic treatment; S23: adding the high molecular adhesive obtained in S21 and the metastable mixed powder obtained in S22 into sufficient ethyl acetate, fully dissolving, and then evaporating after mechanical stirring and heating, to obtain an Al / PTFE metastable composite slurry with adjusted viscosity.

[0008] Optionally, in S21, the fluororubber is fluororubber F2311, and the mass of the ethyl acetate is 5 times that of the fluororubber; in S22, the particle size of the nano-aluminum powder is 50 nm, and the ultrasonic treatment time is 3-5 hours; in S23, the mechanical stirring rate is 40-60 r / min, and the heating evaporation cut-off temperature is 60-80℃.

[0009] Optionally, in S3, the spray head is configured such that, when 3D printing is performed, the Mg / KNO3 energetic slurry obtained in S1 is placed on the outer layer of the shaped energetic material to form a shell structure, and the Al / PTFE metastable composite slurry obtained in S2 is placed on the inner layer of the shaped energetic material to form a core structure.

[0010] Optionally, the shell structure and the core structure are respectively extruded through the double channels of the spray head; wherein the Mg / KNO3 energetic slurry is extruded through the outer channel of the spray head to form the shell structure, and the Al / PTFE metastable composite energetic slurry is extruded through the inner channel arranged in the middle of the outer channel to form the core structure.

[0011] Optionally, the device parameters in S3 include: the feeding speed of the outer layer energetic slurry is 15-30 mm / s, the feeding speed of the inner layer energetic slurry is 9-18 mm / s; the nozzle material is stainless steel, and the double channels of the nozzle are separated by a barrier built in the nozzle or detachably arranged on the nozzle.

[0012] In a second aspect of the present application, a core-shell structured Al / PTFE / Mg / KNO3 quaternary energetic material prepared by the preparation method is provided.

[0013] In a third aspect of the present application, an application of the core-shell structured Al / PTFE / Mg / KNO3 quaternary energetic material in the field of energetic materials is provided.

[0014] The present application has the following beneficial effects:

[0015] (1) The Mg / KNO3 can produce N2, O2 and other gases during the reaction, and the produced oxygen can react with the carbon residue of Al / PTFE to generate CO and other products. By introducing Mg / KNO3 into the original system, the gas production and reaction heat of the system are improved, the reaction residue after the reaction is reduced, the defects and deficiencies of Al / PTFE are effectively improved, and the performance of the entire energetic material system is obviously improved.

[0016] (2) The core-shell structure realizes hierarchical and staged combustion control. The reaction temperature of Mg / KNO3 is low, and it is used as the outer layer material of the energetic material. When ignited, it reacts first to produce a large amount of heat, thereby conducting heat flow to the inner layer Al / PTFE system, further reducing the reaction threshold by using the chemical energy released inside, so that the system can be used to excite the reaction of the entire system under lower external conditions.

[0017] (3) The use of additive manufacturing technology provides a reasonable and feasible process means for the formation of the core-shell structure. By constructing two independent feeding channels, the two slurries are processed into a double-layer structure, the preparation process is simple and easy to operate, and industrialized mass production is realized.

[0018] Therefore, the core-shell structure Al / PTFE / Mg / KNO3 quaternary energetic material based on additive manufacturing technology has potential application prospects in the field of energetic materials.

[0019] In addition, the additional advantages, objects, and features of the present application will be in part apparent and in part pointed out hereinafter in the description, and will be learned from a reading of the following specification and by practice of the application according to the claims. The objects and other advantages of the present application will be realized and attained by the structure and method particularly pointed out in the written description and claims hereof as well as the appended drawings.

[0020] Those skilled in the art will understand that the objects and advantages of the application can be realized and attained by means illustrated in the following detailed description and accompanying drawings. BRIEF DESCRIPTION OF DRAWINGS

[0021] The accompanying drawings, which are included to provide a further understanding of the application and are incorporated in and constitute a part of this application, illustrate embodiments of the application and together with the detailed description serve to explain the principles of the application.

[0022] Figure 1 Flow chart of preparation method of core-shell structure quaternary energetic material in the embodiment of the application;

[0023] Figure 2 SEM-Mapping test diagram of core-shell structure Al / PTFE / Mg / KNO3 quaternary energetic material in the embodiment of the application;

[0024] Figure 3 Limiting oxygen index test diagram of core-shell structure Al / PTFE / Mg / KNO3 quaternary energetic material in the embodiment of the application;

[0025] Figure 4 Internal ballistic performance test result of core-shell structure Al / PTFE / Mg / KNO3 quaternary energetic material in the embodiment of the application. DETAILED DESCRIPTION

[0026] In order to make the objects, technical solutions and advantages of the application clearer, the application will be further described in detail below in combination with embodiments and drawings. The illustrative embodiments of the application and the description thereof are used to explain the application, but are not used to limit the application. It should be noted that, in order to avoid the application being obscured by unnecessary details, only the structures and / or processes closely related to the solutions according to the application are shown in the drawings, and other details not closely related to the application are omitted.

[0027] It should be emphasized that the terms "comprises / comprising" when used in this specification are taken to specify the presence of stated features, elements, or components, but do not preclude the presence or addition of one or more other features, elements, or components.

[0028] In combination Figure 1It can be known that the first aspect of the embodiment of the application is a kind of preparation method of core-shell structure quaternary energetic material, characterized in that, comprising the following specific steps: S1: nano magnesium powder and potassium nitrate powder are dissolved in organic solvent in turn, and Mg / KNO3 energetic slurry is obtained by heating and stirring;S2: nano aluminum powder and PTFE powder are treated by ultrasonic to obtain a metastable mixed powder, then the metastable mixed powder is added to the prepared polymer binder, and Al / PTFE metastable composite slurry is obtained by heating, stirring and evaporation treatment;S3: the Mg / KNO3 energetic slurry obtained in S1 and the Al / PTFE metastable composite slurry obtained in S2 are respectively added to two different barrels of a 3D printer, the equipment parameters of the 3D printer are adjusted, and the two paths are collected into a nozzle with a double-channel blocking effect, and the core-shell structure Al / PTFE / Mg / KNO3 quaternary energetic material is obtained by extrusion molding.

[0029] Optionally, S1 specifically comprises: S11: dissolve nano magnesium powder in sufficient glycerol, heat and stir until fully dissolved, then cool to room temperature to obtain a concentrated magnesium solution;S12: dissolve potassium nitrate powder in sufficient glycerol, and fully stir to obtain a nitro solution;S13: add the concentrated magnesium solution prepared in S11 to the nitro solution prepared in S12 in batches, gradually volatilize the glycerol solvent by heating and stirring to control the overall viscosity of the mixed solution, and obtain the Mg / KNO3 energetic slurry. Wherein, potassium nitrate, as a strong oxidizing substance, can produce various chemical reactions to produce a series of gases such as nitrogen and oxygen;Nano magnesium powder can react with PTFE on one hand, and can also produce gas by reacting with KNO3 on the other hand. The reaction temperature of the two reactions is relatively low, which can be used as an initiator of the whole system by its own low reaction condition, and a large amount of heat is generated to activate the Al / PTFE system to release energy twice. On the one hand, the initial condition requirement of the outside world is reduced, that is, the reaction can be started without providing harsh temperature conditions initially. On the other hand, the gas production of the system is improved, which provides a path for the application of aluminum-based metastable energetic materials in the field.

[0030] Optionally, in S11, the particle size of nano magnesium powder is 100 nm, the heating temperature is 40-50℃, and the stirring rate is 30-45r / min;In S13, the heating is to raise the temperature from room temperature to 40℃ at a speed of 1.6℃ / min, and the stirring rate is 40r / min.

[0031] Optionally, S2 specifically comprises: S21: dissolving fluoro rubber in ethyl acetate to obtain a high molecular adhesive; S22: blending nano-aluminum powder with PTFE powder, and obtaining a metastable mixed powder after ultrasonic treatment; S23: adding the high molecular adhesive obtained in S21 and the metastable mixed powder obtained in S22 into sufficient ethyl acetate to be fully dissolved, and obtaining Al / PTFE metastable composite slurry with adjusted viscosity after mechanical stirring and heating evaporation.

[0032] Optionally, in S21, the fluoro rubber is fluoro rubber F2311, and the mass of ethyl acetate is 5 times that of the fluoro rubber; in S22, the particle size of the nano-aluminum powder is 50 nm, and the ultrasonic treatment time is 3-5 hours; in S23, the mechanical stirring rate is 40-60 r / min, and the heating evaporation cut-off temperature is 60-80 DEG C. Among them, the basis for using fluoro rubber F2311 is that it has stronger intermolecular force with PTFE and Al powder, and has better bonding effect.

[0033] Optionally, in S3, the nozzle is configured to: when 3D printing is performed, the Mg / KNO3 energetic slurry obtained in S1 is placed in the outer layer of the formed energetic material to form a shell structure; and the Al / PTFE metastable composite slurry obtained in S2 is placed in the inner layer of the formed energetic material to form a core structure. The additive manufacturing technology has been widely used in various fields, and as a new type of forming processing method, it has also attracted attention in the field of energetic materials, making the above-mentioned inner and outer layer forming process possible, and solving the problem of difficult forming processing of explosive raw materials.

[0034] Optionally, the shell structure and the core structure are extruded through the double channels of the nozzle; wherein the Mg / KNO3 energetic slurry is extruded through the outer channel of the nozzle to form the shell structure; and the Al / PTFE metastable composite energetic slurry is extruded through the inner channel arranged in the middle of the outer channel to form the core structure.

[0035] Optionally, in S3, the device parameters include: the feeding speed of the outer layer energetic slurry is 15-30 mm / s, and the feeding speed of the inner layer energetic slurry is 9-18 mm / s; the nozzle material is stainless steel, and the double channels of the nozzle are separated by a barrier piece built in the nozzle or detachably arranged on the nozzle. Through the design and modification of the equipment, the raw materials are processed into more delicate sample structures with customized needs, and the advantages of additive manufacturing technology are fully utilized.

[0036] In a second aspect of the present application, an Al / PTFE / Mg / KNO3 quaternary energetic material with core-shell structure prepared by the preparation method is provided. Figure 2Shown is the SEM-Mapping test image of the core-shell structure Al / PTFE / Mg / KNO3 quaternary energetic material in this embodiment.

[0037] like Figure 3 This graph shows the limiting oxygen index (LOI) of the core-shell Al / PTFE / Mg / KNO₃ quaternary energetic material, prepared using the method of the present invention. The three-step LOI test results indicate a LOI of 34.1%. This is because the ignition temperature in the experiment did not reach the initial temperature of the thermite reaction. Oxygen and the decomposition products of KNO₃ acted as combustion supporters, initially reacting with the metal powder to release significant heat, raising the temperature to the point where the thermite reaction conditions would occur, leading to a vigorous reaction. The report shows that when these conditions were met, the sample rapidly ashed, completing the reaction within a short period of time. This result demonstrates the sample's combustibility to a certain extent and its safety. First, the temperature must meet the reaction conditions, and second, the oxygen concentration must reach 34% to support combustion and ignite. For storage at room temperature, neither of these conditions is met, indicating theoretically good stability and storage performance.

[0038] like Figure 4 Figure 3 shows the interior ballistic performance test results of the core-shell structured Al / PTFE / Mg / KNO3 quaternary energetic material in this embodiment. It can be seen intuitively from the figure that compared with the binary components Al / PTFE and Mg / PTFE, the quaternary Al / PTFE / Mg / KNO3 material has a higher combustion rate and explosion pressure, and can produce more gas products, proving its feasibility as a new type of active energetic material.

[0039] The third aspect of the present invention provides an application of a core-shell structured Al / PTFE / Mg / KNO3 quaternary energetic material in the field of energetic materials.

[0040] The present invention will be further described in detail below through specific implementation examples. The following examples are only illustrative and not restrictive, and the scope of protection of the present invention cannot be limited thereto.

[0041] Example 1

[0042] Firstly, Mg / KNO3 energetic slurry was prepared. 1 part of Mg metal powder with a particle size of 100 nm was dissolved in sufficient glycerol, heated to 40°C, and stirred at a speed of 30 r / min. After cooling at room temperature of 25°C and storage, a metal concentrated solution was obtained. 2 parts of KNO3 were dissolved in glycerol and stirred to obtain a nitro solution. The prepared metal concentrated solution was slowly added to the nitro solution obtained in S12, and then the temperature was slowly increased from room temperature to 40°C at a speed of 1.6°C / min. The system was fully stirred at a speed of 40 r / min. The viscosity of the system was controlled by gradually evaporating the glycerol part through temperature, and Mg / KNO3 energetic slurry was obtained.

[0043] Secondly, Al / PTFE metastable composite slurry was prepared. 1 part of fluorine rubber F2311 was fully dissolved in 5 times the mass of ethyl acetate to obtain a high molecular adhesive. Aluminum metal powder with a particle size of 50 nm was blended with PTFE polymer powder, and after ultrasonic homogenization treatment for 3 hours, metastable mixed powder was obtained. The prepared high molecular adhesive and metastable mixed powder were added to sufficient ethyl acetate organic solvent and fully mixed and dissolved. After mechanical stirring at a speed of 40 r / min, the solvent was evaporated by heating to 60°C, and the viscosity was controlled, and Al / PTFE metastable composite slurry was obtained.

[0044] Finally, the obtained Mg / KNO3 energetic slurry and Al / PTFE metastable composite slurry were added to two barrels of a 3D printer, respectively, and finally collected in a specially designed nozzle with a double-layer barrier effect through two channels. The parameters of the 3D printer were controlled as follows: the printing speed of the outer layer was 15 mm / s, and the printing speed of the inner layer was 9 mm / s. After extrusion molding, a core-shell structure Al / Mg / PTFE / KNO3 quaternary energetic material based on additive manufacturing technology was obtained.

[0045] Example 2

[0046] Firstly, Mg / KNO3 energetic slurry was prepared. 1 part of Mg metal powder with a particle size of 100 nm was dissolved in sufficient glycerol, heated to 40°C, and stirred at a speed of 30 r / min. After cooling at room temperature of 25°C and storage, a metal concentrated solution was obtained. 2 parts of KNO3 were dissolved in glycerol and stirred to obtain a nitro solution. The prepared metal concentrated solution was slowly added to the nitro solution obtained in S12, and then the temperature was slowly increased from room temperature to 40°C at a speed of 1.6°C / min. The system was fully stirred at a speed of 40 r / min. The viscosity of the system was controlled by gradually evaporating the glycerol part through temperature, and Mg / KNO3 energetic slurry was obtained.

[0047] Secondly, the Al / PTFE metastable composite slurry is prepared, 1 part of fluoro rubber F2311 is fully dissolved in 5 times of ethyl acetate by mass to obtain a polymer adhesive; aluminum metal powder with a particle size of 50 nm is blended with PTFE polymer powder, and after ultrasonic homogenization treatment for 4 hours, metastable mixed powder is obtained; the polymer adhesive and the metastable mixed powder are added into sufficient ethyl acetate organic solvent for fully mixing and dissolving, and after mechanical stirring at a speed of 50 r / min, the solvent is evaporated by heating to 70°C, and the viscosity is controlled to obtain the Al / PTFE metastable composite slurry.

[0048] Finally, the obtained quaternary energetic precursor is added into two barrels of the 3D printer respectively, and finally gathered into a special nozzle with double-layer barrier effect through two channels, and the parameters of the 3D printer are controlled as follows: the printing speed of the outer layer is 20 mm / s, the printing speed of the inner layer is 12 mm / s, and after extrusion molding processing, the core-shell structure Al / Mg / PTFE / KNO3 quaternary energetic material based on additive manufacturing technology is obtained.

[0049] Example 3

[0050] Firstly, the Mg / KNO3 energetic slurry is prepared, 1 part of Mg metal powder with a particle size of 100 nm is dissolved in sufficient glycerol, heated to 50°C, and fully stirred at a speed of 45 r / min, and after cooling and storage at room temperature of 25°C, a metal concentrated solution is obtained; 2 parts of KNO3 are dissolved in glycerol, and fully stirred to obtain a nitro solution. The prepared metal concentrated solution is slowly added to the nitro solution obtained in S12 in batches, and then the temperature is slowly increased from room temperature to 40°C at a speed of 1.6°C / min, and fully stirred at a speed of 40 r / min. The viscosity is controlled by gradually volatilizing the glycerol part of the system through temperature, and the Mg / KNO3 energetic slurry is obtained.

[0051] Secondly, the Al / PTFE metastable composite slurry is prepared, 1 part of fluoro rubber F2311 is fully dissolved in 5 times of ethyl acetate by mass to obtain a polymer adhesive; aluminum metal powder with a particle size of 50 nm is blended with PTFE polymer powder, and after ultrasonic homogenization treatment for 4 hours, metastable mixed powder is obtained; the polymer adhesive and the metastable mixed powder are added into sufficient ethyl acetate organic solvent for fully mixing and dissolving, and after mechanical stirring at a speed of 50 r / min, the solvent is evaporated by heating to 70°C, and the viscosity is controlled to obtain the Al / PTFE metastable composite slurry.

[0052] Finally, the obtained four-component energetic precursor is added into two barrels of the 3D printer, and then is collected in a special nozzle with double-layer barrier effect through two channels. The parameters of the 3D printer are controlled as follows: the printing speed of the outer layer is 30 mm / s, the printing speed of the inner layer is 18 mm / s, and after the extrusion molding, the core-shell structure Al / Mg / PTFE / KNO3 four-component energetic material based on the additive manufacturing technology is obtained.

[0053] Comparative example

[0054] The Al / PTFE binary energetic material is prepared by using a traditional sintering process. The two powders with a mass ratio of 3:7 are blended at room temperature, and then are pressed, sintered at a temperature of about 300 DEG C, molded, and cooled to obtain a sintered Al / PTFE mixed energetic column. However, one of the disadvantages of the traditional processing technology is that the shape of the mold is limited, and more precise and complex structures such as core-shell structure cannot be processed, and the processing equipment is large and the cost is high.

[0055] Table 1: Performance test comparison table of the core-shell structure Al / Mg / PTFE / KNO3 four-component energetic material of the present application

[0056]

[0057]

[0058] As can be seen from Table 1, the above example 3 is a preferred scheme. After the introduction of KNO3 and Mg powder, the Al / PTFE improves the energy release, reduces the reaction residue, and reduces the initial threshold of the reaction, which shows that the gas produced by the decomposition of KNO3 can further react with the original system residue to improve the reaction energy release and maximize the efficient use of energy; the addition of Mg powder reduces the initial threshold of the chemical reaction, and the pre-ignition reaction can be carried out under lower conditions.

[0059] In addition, the core-shell structure Al / Mg / PTFE / KNO3 four-component energetic material prepared by the present application meets the requirements of new active energetic materials, has the characteristics of low cost, easy production, high energy, and stable performance at room temperature.

[0060] It should be noted that the present application is not limited to the specific configurations and processes described above and shown in the drawings. For the sake of brevity, detailed descriptions of well-known methods are omitted here. In the above examples, several specific steps are described and shown as examples. However, the method process of the present application is not limited to the specific steps described and shown, and those skilled in the art can make various changes, modifications and additions, or change the order of the steps after understanding the spirit of the present application.

[0061] Features described and / or illustrated with respect to one implementation can be used in the same manner or in a similar manner in one or more other implementations and / or in combination with or in place of features of other implementations.

[0062] The above description is merely illustrative of the application and not in limitation, the principles of which can be employed in various and numerous embodiments without departing from the scope of the application.

Claims

1. A method for preparing a core-shell structured quaternary energetic material, characterized in that: The specific steps include: S1: dissolving nano magnesium powder and potassium nitrate powder in an organic solvent successively, heating and stirring to obtain Mg / KNO3 energetic slurry; S2: Ultrasonic treatment of nano-aluminum powder and PTFE powder to obtain a metastable mixed powder, then adding the metastable mixed powder to the prepared polymer binder, heating, stirring, and evaporating to obtain an Al / PTFE metastable composite slurry; S3: The Mg / KNO3 energetic slurry obtained in S1 and the Al / PTFE metastable composite slurry obtained in S2 were added into two different barrels of the 3D printer respectively. The 3D printer equipment parameters were adjusted and the slurries were respectively collected into a nozzle with a dual-channel barrier effect through two passages. The Al / PTFE / Mg / KNO3 quaternary energetic material with a core-shell structure was obtained by extrusion molding.

2. The preparation method according to claim 1, characterized in that S1 specifically includes: S11: dissolving nano-magnesium powder in sufficient amount of glycerol, heating and stirring until fully dissolved, and then cooling to room temperature to obtain a concentrated magnesium metal solution; S12: Dissolve potassium nitrate powder in sufficient glycerol and stir thoroughly to obtain a nitro solution; S13: The concentrated magnesium metal solution prepared in S11 is added in batches to the nitro solution prepared in S12, and the glycerol solvent is gradually evaporated by heating and stirring to control the overall viscosity of the mixed solution to obtain a Mg / KNO3 energetic slurry.

3. The preparation method according to claim 2, wherein: The particle size of the nano magnesium powder in S11 is 100 nm, the heating temperature is 40-50° C., and the stirring rate is 30-45 r / min; The heating in S13 is to increase the temperature from room temperature to 40° C. at a rate of 1.6° C. / min, and the stirring rate is 40 r / min.

4. The preparation method according to claim 1, characterized in that S2 specifically includes: S21: fully dissolving fluororubber in ethyl acetate to obtain a polymer adhesive; S22: blending the nano-aluminum powder with the PTFE powder, and subjecting the mixture to ultrasonic treatment to obtain a metastable mixed powder; S23: adding the polymer binder obtained in S21 and the metastable mixed powder obtained in S22 into a sufficient amount of ethyl acetate to fully dissolve them, and then mechanically stirring and heating to evaporate them to obtain an Al / PTFE metastable composite slurry with adjusted viscosity.

5. The preparation method according to claim 4, characterized in that: The fluororubber in S21 is fluororubber F2311, and the mass of the ethyl acetate is 5 times that of the fluororubber; The particle size of the nano-aluminum powder in S22 is 50 nm, and the ultrasonic treatment time is 3-5 hours; The mechanical stirring rate in S23 is 40-60 r / min, and the cut-off temperature of the heating evaporation is 60-80°C.

6. The preparation method according to claim 1, characterized in that The nozzle in S3 is constructed as follows: When 3D printing is performed, the Mg / KNO3 energetic slurry obtained in S1 is placed on the outer layer of the formed energetic material to form a shell structure; Furthermore, the Al / PTFE metastable composite energetic slurry obtained in S2 is placed in the inner layer of the formed energetic material to form a core structure.

7. The preparation method according to claim 6, characterized in that: The shell structure and the core structure are extruded separately through the dual channels of the nozzle; wherein the Mg / KNO3 energetic slurry is extruded through the outer channel of the nozzle to form a shell structure; Furthermore, the Al / PTFE metastable composite energetic slurry is extruded through an inner layer channel arranged in the middle of the outer layer channel to form a core structure.

8. The preparation method according to claim 6, characterized in that The device parameters described in S3 include: The feeding speed of the outer layer energetic slurry is 15-30 mm / s, and the feeding speed of the inner layer energetic slurry is 9-18 mm / s; The nozzle is made of stainless steel, and the dual channels of the nozzle are blocked by a blocking member that is built into the nozzle and / or detachably arranged on the nozzle.

9. A core-shell structured Al / PTFE / Mg / KNO3 quaternary energetic material prepared according to the preparation method according to any one of claims 1 to 8.

10. Use of the Al / PTFE / Mg / KNO3 quaternary energetic material with a core-shell structure according to claim 9 in the field of energetic materials.

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